This bulletin contains important information about brake systems on Chrysler Corporation vehicles. It's designed to give you an understanding of the materials used in Chrysler brake systems. It will also familiarize you with some normal noises that may occur with a

properly operating system so that you can clearly communicate these details to your customers. Many brake noises are normal and require no repair action. Unusual noises (not considered normal) should be investigated and repaired using approved procedures and Mopar replacement parts as required.

Because of environmental concerns, Chrysler, along with other automotive manufacturers, has eliminated the use of asbestos in most of its products. As a substitute, in some applications,Chrysler adopted semi-metallic brake linings which offer excellent performance. However,because of the metal-to-metal contact with semi-metallic pads, the noises generated by the brake system under normal operation may be greater than vehicles equipped with the previous asbestos linings.

During normal operation, various noises may be heard from the brake system, whether equipped with disc brakes or drum brakes, with or without ABS. To reduce the noise level Chrysler has begun introducing new non-asbestos organic (NAO) brake pads on several models.

COMMON BRAKE NOISES

Depending upon the local environment and individual driving habits, noises from the brake system may become apparent. The following noises are normal and are considered general characteristics of all braking systems (including other vehicle manufacturers). These noises do not indicate improper operation or malfunction in the brake system.

Grinding Noise This noise is common with rear brake drums and on some disc brakes during the first few stops (such as after the vehicle has been parked overnight).This is primarily due to the formation of trace corrosion (light rust) on the metal surfaces during vehicle non-use or storage. This light corrosion is typically cleared from the metal surfaces after an few stops causing the noise to subside.

Trace Squeak/Squeal Noise This typically occurs intermittently with front brake linings at medium speeds when you apply light to medium pressure on the brake pedal. It may also occasionally occur on the rear brakes during the first few stops and/or with cold brakes (especially morning) and/or high humidity.

Groan Noise On automatic transmission equipped vehicles, a slight groan may be heard when coming to an abrupt stop or when allowing the vehicle to creep forward slowly with the brakes slightly applied.

ABS Self Check/Clunk Noise This noise will occur when the vehicle is first started and moved at low speed (e.g. backing or pulling forward out of a parking space). A slight pulsation at the brake pedal may also be felt during the self-test procedure. If any problem is found during self-check, the ABS system will deactivate automatically and the yellow

"Anti-Lock" brake warning light on the instrument panel will light up. If the warning light comes on, the vehicle should be taken to a Chrysler dealership for immediate service. While the ABS system is deactivated (i.e. when the warning light is on)the brake system will operate as a conventional, non-ABS system.

Brake Pad Wear Indicator/Loud Squeal Noise For disc brake pads with wear indicators, an audible continuous warning can be heard when the pads need replacement. This is not a malfunction as wear indicators are designed to perform in this manner. However, this sound does indicate that service is required. Customers that hear this noise should schedule an appointment with a Chrysler dealership as soon as possible to have the brake system inspected.

Noises that do not fit the characteristics of those listed above may be considered unusual especially when the noise becomes constant or when grinding, scraping noises occur, and should be investigated to determine whether a brake problem exists.